The present invention relates to quinazolin-4-ones of the formula I, as described below, their pharmaceutically acceptable salts, pharmaceutical compositions containing them and their use in treating neurodegenerative, psychotropic, and drug and alcohol induced central and peripheral nervous system disorders.
The role of excitatory amino acids, such as glutamic acid and aspartic acid, as the predominant mediators of excitatory synaptic transmission in the central nervous system has been well established. Watkins and Evans, Ann. Rev. Pharmacol. Toxicol., 21, 165 (1981); Monaghan, Bridges, and Cotman, Ann. Rev. Pharmacol. Toxicol., 29, 365 (1989); Watkins, Krogsgaard-Larsen, and Honore, Trans. Pharm. Sci., 11, 25 (1990). These amino acids function in synaptic transmission primarily through excitatory amino acid receptors. These amino acids also participate in a variety of other physiological processes such as motor control, respiration, cardiovascular regulation, sensory perception, and cognition.
Excitatory amino acid receptors are classified into two general types. Receptors that are directly coupled to the opening of cation channels in the cell membrane of the neurons are termed xe2x80x9cionotropic.xe2x80x9d This type of receptor has been subdivided into at least three subtypes, which are defined by the depolarizing actions of the selective agonists N-methyl-D-aspartate (NMDA), xcex1-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), and kainic acid (KA). The second general type is the G-protein or second messenger-linked xe2x80x9cmetabotropicxe2x80x9d excitatory amino acid receptor. This second type, when activated by the agonists quisqualate, ibotenate, or trans-1-aminocyclopentane-1,3-dicarboxylic acid, leads to enhanced phosphoinosoitide hydrolysis in the postsynaptic cell. Both types of receptors appear not only to mediate normal synaptic transmission along excitatory pathways, but also participate in the modification of synaptic connection during development and changes in the efficiency of synaptic transmission throughout life. Schoepp, Bockaert, and Sladeczek. Trends in Pharmacol. Sci., 11, 508 (1990); McDonald and Johnson, Brain Research Reviews, 15, 41 (1990).
The excessive or inappropriate stimulation of excitatory amino acid receptors leads to neuronal cell damage or loss by way of a mechanism known as excitotoxicity. This process has been suggested to mediate neuronal degeneration in a variety of conditions. The medical consequences of such neuronal degeneration makes the abatement of these degenerative neurological processes an important therapeutic goal.
Excitatory amino acid excitotoxicity has been implicated in the pathophysiology of a number of neurological disorders. This excitotoxicity has been implicated in the pathophysiology of acute and chronic neurodegenerative conditions including stroke, cerebral ischemia, spinal cord trauma, head trauma, Alzheimer""s Disease, Huntington""s Chorea, amyotrophic lateral sclerosis, epilepsy, AIDS-induced dementia, perinatal hypoxia, hypoxia (such as conditions caused by strangulation, surgery, smoke inhalation, asphyxiation, drowning, choking, electrocution or drug or alcohol overdose), cardiac arrest, hypoglycemic neuronal damage, ocular damage and retinopathy, idiopathic and drug-induced Parkinson""s Disease and cerebral deficits subsequent to cardiac bypass surgery and grafting. Other neurological conditions, that are caused by glutamate dysfunction, require neuromodulation. These other neurological conditions include muscular spasms, migraine headaches, urinary incontinence, psychosis, addiction withdrawal (such as alcoholism and drug addiction including opiate, cocaine and nicotine addiction), opiate tolerance, anxiety, emesis, brain edema, chronic and acute pain, convulsions, retinal neuropathy, tinnitus and tardive dyskinesia. The use of a neuro-protective agent, such as an AMPA receptor antagonist, is believed to be useful in treating these disorders and/or reducing the amount of neurological damage associated with these disorders. The excitatory amino acid receptor (EAA) antagonists are also useful as analgesic agents.
Several studies have shown that AMPA receptor antagonists are neuroprotective in focal and global ischemia models. The competitive AMPA receptor antagonist NBQX (2,3-dihydroxy-6-nitro-7-sulfamoylbenzo[f-]quinoxaline) has been reported effective in preventing global and focal ischemic damage. Sheardown et al., Science, 247, 571 (1900); Buchan et al., Neuroreport, 2, 473 (1991); LePeillet et al., Brain Research, 571, 115 (1992). The noncompetitive AMPA receptor antagonist GKYI 52466 has been shown to be an effective neuroprotective agent in rat global ischemia models. LaPeillet et al., Brain Research, 571, 115 (1992). These studies strongly suggest that the delayed neuronal degeneration in brain ischemia involves glutamate excitotoxicity mediated at least in part by AMPA receptor activation. Thus, AMPA receptor antagonists may prove useful as neuroprotective agents and improve the neurological outcome of cerebral ischemia in humans.
The present invention relates to compounds of the formula 
wherein A is a benzo or thieno fused aromatic ring;
B is phenyl, pyridyl or pyrimidyl;
X is N or CH;
Y and Z, taken together, i.e., Y-Z, are either xe2x80x94CH2NHxe2x80x94 or xe2x80x94NHCH2xe2x80x94;
R1 is selected from hydrogen, (C1-C6)alkyl optionally substituted with from one to three fluorine atoms, cyano, halo, amino, nitro and (C1-C6)alkoxy optionally substituted with from one to three fluorine atoms;
R2 is halo, cyano, (C1-C6) alkyl optionally substituted with from one to three fluorine atoms, nitro, amino, (C1-C6)alkylthio, (C1-C6)alkoxy optionally substituted with from one to three fluorine atoms, hydroxy, Hxe2x80x94C(xe2x95x90O)xe2x80x94, (C1-C6)alkyl-Oxe2x80x94C(xe2x95x90O)xe2x80x94 or NH2-C(xe2x95x90O)xe2x80x94;
R3 and R4 are selected, independently, from hydrogen, (C1-C6)alkyl optionally substituted with from one to three fluorine atoms, halo, cyano, hydroxy (C1-C6)alkoxy optionally substituted with from one to three fluorine atoms, xe2x80x94C(xe2x95x90O)H, xe2x80x94CH2OR5 and xe2x80x94CH2NR6R7;
R5 is hydrogen, (C1-C6)alkyl or xe2x80x94C(xe2x95x90O)(C1-C6)alkyl; and
R6 and R7 are selected, independently, from hydrogen, (C1-C6)alkyl, xe2x80x94C(xe2x95x90O)H and xe2x80x94C(xe2x95x90O)(C1-C6)alkyl;
or R6 and R7, taken together with the nitrogen to which they are attached, form a four to seven membered saturated or unsaturated ring wherein one of the carbon atoms of such ring may optionally be replaced by oxygen or nitrogen (for example, a morpholine, piperidine, pyrrolidine, piperizine, azetidine, pyrrole, pyridine or oxazoline ring);
and the pharmaceutically acceptable salts of such compounds.
The present invention also relates to the pharmaceutically acceptable acid addition salts of compounds of the formula I. The acids which are used to prepare the pharmaceutically acceptable acid addition salts of the aforementioned base compounds of this invention are those which form non-toxic acid addition salts, i.e., salts containing pharmacologically acceptable anions, such as the hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, acetate, lactate, citrate, acid citrate, tartrate, bitartrate, succinate, maleate, fumarate, gluconate, saccharate, benzoate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate and pamoate [i.e., 1,1xe2x80x2-methylene-bis-(2-hydroxy-3-naphthoate)]salts.
Examples of preferred compounds of the formula I are those wherein R1 is fluoro.
Other Examples of preferred compounds of the formula I are those wherein Y-Z is xe2x80x94CH2NHxe2x80x94, ring A is a benzo ring and R1 is fluoro.
Other examples of preferred compounds of the formula I are wherein R2 is halo, methyl or trifluoromethyl.
Other examples of preferred compounds of the formula I are those wherein Y-Z is xe2x80x94CH2NHxe2x80x94, ring A is a benzo ring, R1 is fluoro, ring B is 2-pyridyl or phenyl and R3 is cyano, fluoro, methyl or xe2x80x94CH2NR6R7.
Other more specific embodiments of this invention are the following:
(a) compounds of the formula I wherein ring A is benzo;
(b) compounds of the formula I wherein ring A is thieno;
(c) compounds of the formula I wherein ring B is phenyl;
(d) compounds of the formula I wherein ring B is a pyridine or pyrimidine ring; and
(e) compounds of the formula I wherein R6 and R7, together with the nitrogen to which they are attached, form a morpholine or pyrrolidine ring.
Examples of specific compounds of this invention are:
3-(2-chloro-phenyl)-6-fluoro-2-[(pyridin-2-ylmethyl)-amino]-3H-quinazolin-4-one;
6-fluoro-3-(2-methyl-phenyl)-2-[(pyridin-2-ylmethyl)-amino]-3H-quinazolin-4-one;
3-(2-chloro-phenyl)-6-fluoro-2-[(2-fluorophenyl-methyl)-amino]-3H-quinazolin-4-one;
3-(2-chloro-phenyl)-2-[(2-cyanophenyl-methyl)-amino]-6-fluoro-3H-quinazolin-4-one;
3-(2-chloro-phenyl)-2-[(6-diethylaminomethylpyridin-2-ylmethyl)-amino]-6-fluoro-3H-quinazolin-4-one;
3-(2-chloro-phenyl)-6-fluoro-2-[(6-pyrrolidin-1-ylmethyl-pyridin-2-ylmethyl)-amino]-3H-quinazolin-4-one;
3-(2-chloro-phenyl)-2-[(3-pyrrolidin-1-ylmethyl-phenylamino)-methyl]-3H-thieno[3,2-d]pyrimidin-4-one;
3-(2-methyl-phenyl)-2-[(3-pyrrolidin-1-ylmethyl-phenylamino)-methyl]-3H-thieno[3,2-d]pyrimidin-4-one;
3-(2-chloro-phenyl)-2-[(2-fluoro-phenylamino)-methyl]-3H-thieno[3,2-d]pyrimidin-4-one;
3-(2-chloro-pyrid-3-yl)-2-[(3-pyrrolidin-1-ylmethyl-phenylamino)-methyl]-3H-thieno[3,2-d]pyrimidin-4-one;
2-{[3-(2-chloro-pyrid-3-yl)-4-oxo-3,4-dihydro-thieno[3,2-d]pyrimidin-2-ylmethyl]-amino}-benzonitrile;
3-(2-chloro-phenyl)-2-[(3-pyrrolidin-1-ylmethyl-phenylamino)-methyl]-3H-quinazolin-4-one;
6-chloro-3-(2-chloro-phenyl)-2-[(3-pyrrolidin-1-ylmethyl-phenylamino)-methyl]-3H-quinazolin-4-one;
6-chloro-3-(2-chloro-phenyl)-2-[(3-diethylaminomethyl-phenylamino)-methyl]-3H-quinazolin-4-one;
6-chloro-3-(2-chloro-pyrid-3-yl)-2-[(3-diethylaminomethyl-phenylamino)-methyl]-3H-quinazolin-4-one;
6-chloro-3-(2-trifluoromethyl-phenyl)-2-[(3-diethylaminomethyl-phenylamino)-methyl]-3H-quinazolin-4-one;
2-{[3-(2-chloro-pyridin-3-yl)-4-oxo-3,4-dihydro-quinazolin-2-ylmethyl]-amino}-benzonitrile;
2-{[3-(2-methyl-pyridin-3-yl)-4-oxo-3,4-dihydro-quinazolin-2-ylmethyl]-amino}-benzonitrile;
2-{[6-fluoro-3-(2-methyl-phenyl)-4-oxo-3,4-dihydro-quinazolin-2-ylmethyl]-amino}-nicotinonitrile; and
2-{[3-(2-chloro-phenyl)-4-oxo-3,4-dihydro-quinazolin-2-ylmethyl]-amino}-nicotinonitrile.
This invention also relates to a pharmaceutical composition for treating a condition selected from stroke, cerebral ischemia, spinal cord trauma, head trauma, Alzheimer""s Disease, Huntington""s Chorea, amyotrophic lateral sclerosis, epilepsy, AIDS-induced dementia, muscular spasms, migraine headaches, urinary incontinence, psychosis, convulsions, perinatal hypoxia, hypoxia (such as conditions caused by strangulation, surgery, smoke inhalation, asphyxiation, drowning, choking, electrocution or drug or alcohol overdose), cardiac arrest, hypoglycemic neuronal damage, opiate tolerance, addiction withdrawal (such as alcoholism and drug addiction including opiate, cocaine and nicotine addiction), ocular damage, retinopathy, retinal neuropathy, tinnitus, idiopathic and drug induced Parkinson""s Disease, anxiety, emesis, brain edema, chronic or acute pain, tardive dyskinesia and cerebral deficits subsequent to cardiac bypass surgery and grafting, in a mammal, comprising an amount of a compound of formula I that is effective in treating such condition and a pharmaceutically acceptable carrier.
This invention also relates to a method of treating a condition selected from stroke, cerebral ischemia, spinal cord trauma, head trauma, Alzheimer""s Disease, Huntington""s Chorea, amyotrophic lateral sclerosis, epilepsy, AIDS-induced dementia, muscular spasms, migraine headaches, urinary incontinence, psychosis, convulsions, perinatal hypoxia, hypoxia (such as conditions caused by strangulation, surgery, smoke inhalation, asphyxiation, drowning, choking, electrocution or drug or alcohol overdose), cardiac arrest, hypoglycemic neuronal damage, opiate tolerance, addiction withdrawal (such as alcoholism and drug addiction including opiate, cocaine and nicotine addiction), ocular damage, retinopathy, retinal neuropathy, tinnitus, idiopathic and drug induced Parkinson""s Disease, anxiety, emesis, brain edema, chronic or acute pain, tardive dyskinesia and cerebral deficits subsequent to cardiac bypass surgery and grafting, in a mammal, comprising administering to a mammal in need of such treatment an amount of a compound of formula I that is effective in treating such condition.
This invention also relates to a pharmaceutical composition for treating a disorder or condition, the treatment of which can be effected or facilitated by reducing or inhibiting glutamate neurotransmission in a mammal, comprising an amount of a compound of formula I, or a pharmaceutically effective salt thereof, that is effective in treating such disorder or condition and a pharmaceutically acceptable carrier.
This invention also relates to a method of treating a disorder or condition, the treatment or prevention of which can be effected or facilitated by reducing or inhibiting glutamate neurotransmission in a mammal, comprising administering to a mammal in need of such treatment an amount of a compound of formula I, or a pharmaceutically effective salt thereof, that is effective in treating such disorder or condition.
This invention also relates to a pharmaceutical composition for treating a condition selected from stroke, cerebral ischemia, spinal cord trauma, head trauma, Alzheimer""s Disease, Huntington""s Chorea, amyotrophic lateral sclerosis, epilepsy, AIDS-induced dementia, muscular spasms, migraine headaches, urinary incontinence, psychosis, convulsions, perinatal hypoxia, hypoxia (such as conditions caused by strangulation, surgery, smoke inhalation, asphyxiation, drowning, choking, electrocution or drug or alcohol overdose), cardiac arrest, hypoglycemic neuronal damage, opiate tolerance, addiction withdrawal (such as alcoholism and drug addiction including opiate, cocaine and nicotine addiction), ocular damage, retinopathy, retinal neuropathy, tinnitus, idiopathic and drug induced Parkinson""s Disease, anxiety, emesis, brain edema, chronic or acute pain, tardive dyskinesia and cerebral deficits subsequent to cardiac bypass surgery and grafting, in a mammal, comprising an AMPA receptor antagonizing effective amount of a compound of formula I, or a pharmaceutically salt thereof, and a pharmaceutically acceptable carrier.
This invention also relates to a method for treating a condition selected from stroke, cerebral ischemia, spinal cord trauma, head trauma, Alzheimer""s Disease, Huntington""s Chorea, amyotrophic lateral sclerosis, epilepsy, AIDS-induced dementia, muscular spasms, migraine headaches, urinary incontinence, psychosis, convulsions, perinatal hypoxia, hypoxia (such as conditions caused by strangulation, surgery, smoke inhalation, asphyxiation, drowning, choking, electrocution or drug or alcohol overdose), cardiac arrest, hypoglycemic neuronal damage, opiate tolerance, addiction withdrawal (such as alcoholism and drug addiction including opiate, cocaine and nicotine addiction), ocular damage, retinopathy, retinal neuropathy, tinnitus, idiopathic and drug induced Parkinson""s Disease, anxiety, emesis, brain edema, chronic or acute pain, tardive dyskinesia and cerebral deficits subsequent to cardiac bypass surgery and grafting, in a mammal, comprising administering to a mammal requiring such treatment an AMPA receptor antagonizing effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof.
This invention also relates to a pharmaceutical composition for treating a disorder or condition, the treatment of which can be effected or facilitated by reducing or inhibiting glutamate neurotransmission in a mammal, comprising an AMPA receptor antagonizing effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.
This invention also relates to a method for treating a disorder or condition, the treatment of which can be effected or facilitated by reducing or inhibiting glutamate neurotransmission in a mammal, comprising administering to a mammal requiring such treatment an AMPA receptor antagonizing effective amount of a compound of formula I or a pharmaceutically acceptable salt thereof.
Unless otherwise indicated, the alkyl groups referred to herein, as well as the alkyl moieties of other groups referred to herein (e.g., alkoxy), may be linear or branched, and they may also be cyclic (e.g., cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl) or be linear or branched and contain cyclic moieties.
The term xe2x80x9ctreatingxe2x80x9d, as used herein, refers to reversing, alleviating, inhibiting the progress of, or preventing the disorder or condition to which such term applies, or one or more symptoms of such disorder or condition. The term xe2x80x9ctreatmentxe2x80x9d, as used herein, refers to the act of treating, as xe2x80x9ctreatingxe2x80x9d is defined immediately above.
Unless otherwise indicated, xe2x80x9chaloxe2x80x9d and xe2x80x9chalogenxe2x80x9d, as used herein, refer to fluorine, bromine, chlorine or iodine.
Compounds of the formula I may have chiral centers and therefore may exist in different enantiomeric and diastereomic forms. This invention relates to all optical isomers and all stereoisomers of compounds of the formula I and mixtures thereof, and to all pharmaceutical compositions and methods of treatment defined above that contain or employ them, respectively.
Due to the substituent on the carbon at position xe2x80x9c2xe2x80x9d and the carbonyl group on the carbon at position xe2x80x9c4xe2x80x9d of the quinazolin-4-one of formula I, the ring attached to the nitrogen at position xe2x80x9c3xe2x80x9d can not rotate freely. This restricted rotation means that compounds of the formula I exist in two isomeric forms or atropisomers. These atropisomers can be separated.
This invention includes, for example, those stereoisomers of compounds of the formula I that are atropisomers. Atropisomers are isomeric compounds that are chiral, i.e., each isomer is not superimposable on its mirror image and the isomers, once separated, rotate polarized light in equal but opposite directions. Atropisomers are distinguished from enantiomers in that atropisomers do not possess a single asymmetric atom. Such compounds are conformational isomers which occur when rotation about a single bond in the molecule is prevented or greatly slowed as a result of steric interactions with other parts of the molecule and the substituents at both ends of the single bond are unsymmetrical. A detailed account of atropisomers can be found in Jerry March, Advanced Organic Chemistry, 101-102 (4th ed. 1992) and in Oki, Top. Stereochem., 14, 1-81 (1983).
The following structure depicts the atropisomerism of the compound of formula I. 
The bold lines in formula Ia indicate that the bolded atoms, and the groups attached thereto, are sterically restricted so as to exist orthogonally above the plane of the quinazolinone ring. This steric restriction is due to a rotational energy barrier preventing free rotation about the single bond connecting the nitrogen at position xe2x80x9c3xe2x80x9d of the quinazolinone ring to the X-containing (i.e., phenyl or pyridyl) aryl group.
Formulas I and Ia above include compounds identical to those depicted but for the fact that one or more hydrogen, carbon or other atoms are replaced by isotopes thereof. Such compounds are useful as research and diagnostic tools in metabolism pharmacokinetic studies and in binding assays. Specific applications in research include radioligand binding assays, autoradiography studies and in vivo binding studies.
The compounds of formula I can be prepared according to the methods of Scheme 1. In the reaction Scheme and discussion that follow, unless otherwise indicated, rings A and B and substituents R1 through R7, Y and Z are as defined above for formula I. 
Scheme 1 illustrates methods of preparing intermediates of the formula II, which can then be converted into compounds of the formula I. Referring to Scheme 1, a compound of the formula V can be converted into an acetamide of the formula IV by reactioning it with acetyl chloride or acetic anhydride in the presence of a base in a reaction inert solvent. Suitable solvents include methylene chloride, dimethoxyethane, t-butyl methyl ether, dichloroethane, tetrahydrofuran and dioxane. Suitable bases include trialkylamines such as triethylamine and tributylamine, dimethylaminopyridine and potassium carbonate, preferably triethylamine. The temperature of this reaction is in the range from about 0xc2x0 C. to about 100xc2x0 C. for about 1 hour to about 10 hours, preferably at about 0xc2x0 C. to 30xc2x0 C. for about 3 hours.
The acetamide of formula IV can be cyclized to form a compound of the formula III by reaction with a dehydrating agent, in the presence of a catalyst, in a dry reaction inert solvent. Suitable dehydrating agents include acetic anhydride, phosphorus pentoxide, dicyclohexylcarbodiimide, and acetyl chloride, preferably acetic anhydride. Suitable catalysts include sodium or potassium acetate, acetic acid, p-toluene sulfonic acid, or boron trifluoride etherate, preferably sodium acetate. Suitable solvents include dioxane, toluene, diglyme or dichloroethane, preferably dioxane. The temperature for this reaction can range from about 0xc2x0 C. to about 150xc2x0 C. and the reaction is generally carried out for about 1 hour to about 24 hours. Preferably, the reaction is conducted at about 80xc2x0 C. to 100xc2x0 C. for about 3 to 10 hours.
Alternatively, the compound of formula V can be converted directly into a compound of formula III by reacting it with acetic anhydride in the presence of an acid catalyst in a solvent. Examples of acid catalysts that can be used are acetic acid, sulfuric acid and p-toluene sulfonic acid. Acetic acid is preferred. Examples of solvents that can be used are toluene and xylene. Acetic acid is also the preferred solvent. The temperature for this reaction can range from about 20xc2x0 C. to about 150xc2x0 C. and the reaction is typically carried at for about 10 minutes to about 10 hours. The reaction is preferably carried out at about 80xc2x0 C. to 120xc2x0 C. for about 2 to 5 hours.
The compound of formula III, formed by either of the above methods, can then be reacted with an amine of the formula 
in a polar protic solvent, in the presence of an acid catalyst, to form a compound of the formula II. Suitable acid catalysts include acetic acid, p-toluene sulfonic acid and sulfuric acid, with acetic acid being preferred. Suitable polar protic solvents include acetic acid, methanol, ethanol and isopropanol, with acetic acid being preferred. This reaction is generally carried out at a temperature from about 20xc2x0 C. to about 150xc2x0 C. for about 1 hour to about 24 hours, preferably for about 6 hours at about 80xc2x0 C. to 120xc2x0 C.
Alternatively, a compound of the formula IV can be directly converted to a compound of the formula II by reaction with a dehydrating agent, an amine of the formula VIII, as described above, and a base, in a reaction inert solvent. Examples of dehydrating agents that can be used are phosphorous trichloride, phosphorous oxychloride, phosphorous pentachloride and thionyl chloride, with phosphorous trichloride being preferred. Suitable bases include pyridine, lutidine, diisopropylethylamine, dimethylaminopyridine, triethylamine and N-methyl morpholine. Suitable solvents include toluene, cyclohexane, benzene and xylene. Preferably, pyridine is used as the base and the reaction is carried at in a toluene solvent. Under some circumstances, when the combined reactants are a liquid, the reaction may be run neat. The temperature can range from about 50xc2x0 C. to about 150xc2x0 C., and the reaction is generally allowed to run for about 1 hour to about 24 hours. It is preferably carried out at about 80xc2x0 C. to 1 20xc2x0 C. for about 2-8 hours.
Scheme 2 illustrates the synthesis of compounds of formula I from the corresponding compounds of formula II. Referring to Scheme 2, reaction of a compound of the formula II with dimethylformamide dimethyl acetal complex (DMFxe2x80xa2DMA) in dimethylformamide (DMF) at a temperature from about 50xc2x0 C. to about 180xc2x0 C., preferably from about 100xc2x0 C. to about 150xc2x0 C. yields, the corresponding amines of formula IX.
The aldehydes of formula X can be formed by reacting the corresponding enamines of formula IX with sodium periodate (NaIO4) or potassium permanganate (KMnO4) in a solvent mixture containing water and an organic solvent such as ether, dimethoxyethane (DME), dioxane and tetrahydrofuran (THF), preferably THF, at a temperature from about 0xc2x0 C. to about 80xc2x0 C., preferably at about room temperature. An aqueous buffer is preferably added to the reaction mixture to maintain a pH of about 7.
The aldehydes formed in the foregoing reaction can be converted into the corresponding compounds of formula I by reductive amination using, as the amine, a compound of the formula 
The reductive amination can be carried out at a temperatures ranging from about 0xc2x0 C. to about 150xc2x0 C., preferably from about 20xc2x0 C. to 100xc2x0 C., using any of a variety of reducing agents, for example, sodium cyanoborohydride (NaBH3CN), sodium triacetoxyborohydride (NaBH(OAc)3), or sodium borohydride (NaBH4), in a solvent such as methylene chloride, 1,2-dichlorethane, toluene, benzene, acetic acid, methanol and ethanol. The preferred solvent will vary with the choice of reducing agent, as will be obvious to those of skill in the art. Reduction can also be accomplished by hydrogenation, using hydrogen gas at a pressure of about 1 to about 5 atmospheres, a catalyst selected from rhodium, palladium, palladium hydroxide and platinum oxide. Hydrogenation can also be carried out using a chemical hydrogen source such as ammonium formate or formic acid. Such transfer hydrogenation will use the same catalysts described above. The reductive amination may be optionally carried out in the presence of a dehydrating agent such as sodium sulfate, magnesium sulfate, calcium sulfate or molecular sieves.
The reductive amination described above proceeds through an imine intermediate, as depicted in Scheme 3. If so desired, the imine intermediate of formula XIII can be formed (and optionally isolated) by predehydrating the reaction mixture using an acid such as p-toluenesulfonic acid or sulfuric acid, with or without azeotropic removal of water, prior to addition of the reducing agent. Treatment of the imine of formula XIII under any of the previously described conditions provides the corresponding compound of formula I.
Scheme 4 illustrates an alternate method of preparing compounds of the formula II from those of formula V. The compounds of formula II, so formed, can then be converted into the desired compounds of formula I using the procedure illustrated in Scheme 2 and described above. Referring to Scheme 4, a compound of the formula V is reacted with a coupling reagent, an amine of the formula VIII, as described above, and a base in a reaction inert solvent to form a compound of the formula VI. Examples of suitable coupling reagents that activate the carboxylic functionality are dicyclohexylcarbodiimide, N-3-dimethylaminopropyl-Nxe2x80x2-ethylcarbodiimide, 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline(EEDQ), carbonyl diimidazole (CDI), and diethylphosphorylcyanide. Suitable bases include dimethylaminopyridine (DMAP) and triethylamine. Dimethylaminopyridine is preferred. A catalyst such as hydroxybenzotriazole (HBT) may also be used. The coupling is conducted in an inert solvent, preferably an aprotic solvent. Suitable solvents include acetonitrile, dichloromethane, dichloroethane, and dimethylformamide. The preferred solvent is dichloromethane. The temperature of the aforesaid reaction is generally from about xe2x88x9230 to about 80xc2x0 C., and is preferably about 0 to about 25xc2x0 C.
The compound of formula VI can be converted into a compound of the formula VII by reaction with acetyl chloride or acetic anhydride in the presence of a base (e.g., a trialkylamine such as triethylamine or tributylamine, dimethylaminopyridine or potassium carbonate) in a reaction inert solvent. Suitable solvents include methylene chloride, tetrahydrofuran and chloroform, preferably methylene chloride. Preferably, triethylamine is used as the base. This reaction is generally carried at a temperature from about 0xc2x0 C. to about 35xc2x0 C. for about 1 hour to about 10 hours, preferably at about 30xc2x0 C. for about 3 hours.
The compound of formula VII is cyclized to a compound of formula II by reaction with triphenylphosphine, a base, and a dialkyl azodicarboxylate in a reaction inert solvent. Examples of bases that can be used in this reaction are pyridine, triethylamine and 4-dimethylaminopyridine, with 4-dimethylaminopyridine being preferred. Appropriate solvents include dimethylformamide, tetrahydrofuran and dioxane, with dioxane being preferred. Typically, this reaction is conducted at a temperature from about 25xc2x0 C. to about 125xc2x0 C. for about 1 hour to about 24 hours, preferably from about 80xc2x0 C. to 120xc2x0 C. for about 8 to 15 hours.
Compounds of formula II can also be made according to the methods described in Miyashita, et al., Heterocycles. 42, 2, 691-699 (1996).
Scheme 5 illustrates a method of preparing compounds of the formula I wherein YZ is NHCH2. Referring to Scheme 5, a 2-aminocarboxylic acid of the formula V is reacted with an isothiocyanate of the formula XIV to form the thione product of formula XV. This reaction is generally carried out in a solvent such as acetic acid, dioxane, tetrahydrofuran, chloroform, dichloroethane or benzene, preferably acetic acid, at a temperature from about 20xc2x0 C. to about 150xc2x0 C., preferably at about the reflux temperature of the solvent, for about 0.25 hours to 24 hours, generally for about 1-6 hours.
The resulting thiones of formula XV can then be converted into the chlorinated compounds of formula XVI by reaction with a chlorinating agent such as phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, thionyl chloride, sulfuryl chloride or a mixture of one or more of these chlorinating agents, preferably a mixture of phosphorus oxychloride and phosphorus pentachloride. The reaction may be carried out without a solvent or in an inert solvent such as toluene, benzene, chloroform, dichloroethane or dimethoxyethane. Reaction without a solvent is preferred unless the reagents do not freely form a solution. This reaction is generally carried out at a temperature from about 20xc2x0 C. to about 180xc2x0 C., preferably from about 80xc2x0 C. to 150xc2x0 C. for about 0.5 to 24 hours, preferably for about 1-6 hours.
Reaction of the chlorides of formula XVI with an amine of the formula 
yields the corresponding compounds of formula I wherein YZ is NHCH2. This reaction is typically carried out in a solvent such as methanol, ethanol, propanol, isopropanol, tetrahydrofuran, dioxane or dichloroethane, with ethanol being preferred. The reaction is allowed to proceed for about 1-24 hours, at a temperature from about 20xc2x0 C. to about 150xc2x0 C. Preferably, the reaction is allowed to proceed for about 4-16 hours at a temperature of about 80xc2x0 C. to 120xc2x0 C.
Unless indicated otherwise, the pressure of each of the above reactions is not critical. Generally, the reactions will be conducted at a pressure of about one to about three atmospheres, preferably at ambient pressure (about one atmosphere).
The compounds of the formula I which are basic in nature are capable of forming a wide variety of different salts with various inorganic and organic acids. Although such salts must be pharmaceutically acceptable for administration to animals, it is often desirable in practice to initially isolate a compound of the formula I from the reaction mixture as a pharmaceutically unacceptable salt and then simply convert the latter back to the free base compound by treatment with an alkaline reagent, and subsequently convert the free base to a pharmaceutically acceptable acid addition salt. The acid addition salts of the base compounds of this invention are readily prepared by treating the base compound with a substantially equivalent amount of the chosen mineral or organic acid in an aqueous solvent medium or in a suitable organic solvent such as methanol or ethanol. Upon careful evaporation of the solvent, the desired solid salt is obtained.
The acids which are used to prepare the pharmaceutically acceptable acid addition salts of the base compounds of this invention are those which form non-toxic acid addition salts, i.e., salts containing pharmacologically acceptable anions, such as hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate or bisulfate, phosphate or acid phosphate, acetate, lactate, citrate or acid citrate, tartrate or bitartrate, succinate, maleate, fumarate, gluconate, saccharate, benzoate, methanesulfonate and pamoate [i.e., 1,1xe2x80x2-methylene-bis-(2-hydroxy-3-naphthoate)] salts.
The compounds of the formula I and the pharmaceutically acceptable salts thereof (hereinafter, also referred to as the active compounds of the invention) are useful for the treatment of neurodegenerative, psychotropic and drug and alcohol induced central and peripheral nervous system disorders and are potent AMPA receptor antagonists. The active compounds of the invention may therefore be used in the treatment or prevention of stroke, cerebral ischemia, spinal cord trauma, head trauma, Alzheimer""s Disease, Huntington""s Chorea, amyotrophic lateral sclerosis, epilepsy, AIDS-induced dementia, muscular spasms, migraine headaches, urinary incontinence, psychosis, convulsions, perinatal hypoxia, hypoxia (such as conditions caused by strangulation, surgery, smoke inhalation, asphyxiation, drowning, choking, electrocution or drug or alcohol overdose), cardiac arrest, hypoglycemic neuronal damage, opiate tolerance, addiction withdrawal (such as alcoholism and drug addiction including opiate, cocaine and nicotine addiction), ocular damage, retinopathy, retinal neuropathy, tinnitus, idiopathic and drug induced Parkinson""s Disease, anxiety, emesis, brain edema, chronic or acute pain, tardive dyskinesia and cerebral deficits subsequent to cardiac bypass surgery and grafting.
The in vitro and in vivo activity of the compounds of the invention for AMPA receptor antagonism can be determined by methods available to one of ordinary skill in the art. One method for determining the activity of the compounds of the invention is by inhibition of pentylenetetrazol (PTZ)-induced seizures. Another method for determining the activity of the compounds of the invention is by blockade of AMPA receptor activation-induced 45Ca2+ uptake.
One specific method for determining inhibition of pentylenetetrazol (PTZ)-induced seizures is as follows. The activity of the compounds of the invention for inhibition of pentylenetetrazol (PTZ)-induced seizures in mice can be determined according to the following procedure. This assay examines the ability of compounds to block seizures and death produced by PTZ. Measures taken are latency to clonic and tonic seizures, and death. ID50s are determined based on percent protection.
Male CD-1 mice from Charles River, weighing 14-16 g on arrival and 25-35 g at the time of testing, serve as subjects for these experiments. Mice are housed 13 per cage under standard laboratory conditions on a L:D/7 a.m.:7 p.m. lighting cycle for at least 7 days prior to experimentation. Food and water are available ad libitum until the time of testing.
All compounds are administered in a volume of 10 ml/kg. Drug vehicles will depend on compound solubility, but screening will typically be done using saline, distilled water, or E:D:S/5:5:90 (5% emulphor, 5% DMSO, and 90% saline) as the injection vehicle.
Mice are administered the test compounds or vehicle (i.p., s.c., or p.o.) and are placed into plexiglass cages in groups of five. At a predetermined time after these injections, mice are given an injection of PTZ (i.p., 1 20 mg/kg) and placed into individual plexiglass cages. Measures taken during this five minute test period are: (1) latency to clonic seizures, (2) latency to tonic seizures, and (3) latency to death. Treatment groups are compared to the vehicle-treated group by Kruskal-Wallis Anova and Mann-Whitney U tests (Statview). Percent protection is calculated for each group (number of subjects not showing seizure or death as indicated by a score of 300 secs) at each measure. ID50""s are determined by prohibit analysis (Biostat).
Another method for determining the activity of the compounds is to determine the effect of the compounds on motor coordination in mice. This activity can be determined according to the following procedure.
Male CD-1 mice from Charles River, weighing 14-16 g on arrival and 23-35 g at the time of testing, serve as subjects for these experiments. Mice are housed 13 per cage under standard laboratory conditions on a L:D/7 a.m.:7 p.m. lighting cycle for at least 7 days prior to experimentation. Food and water are available ad libitum until the time of testing.
All compounds are administered in a volume of 10 ml/kg. Drug vehicles will depend on compound solubility, but screening will typically be done using saline, distilled water, or E:D:S/5:5:90 (5% emulphor, 5% DMSO, and 90% saline) as the injection vehicle.
The apparatus used in these studies consists of a group of five 13.34xc3x9713.34 cm wire mesh squares suspended on 11.43 cm steel poles connected to a 165.1 cm pole which is elevated 38.1 cm above the lab bench. These wire mesh squares can be turned upside-down.
Mice are administered test compounds or vehicle (i.p., s.c., or p.o) and are placed into plexiglass cages in groups of five. At a predetermined time after these injections, mice are placed on top of the wire mesh squares and flipped so that they are suspended upside-down. During the one minute test, mice are rated 0 if they fall off the screen, 1 if they hang on upside-down, or 2 if they climb up onto the top. Treatment groups are compared to the vehicle-treated group with Kruskal-Wallis and Mann-Whitney U tests (Statview).
One specific method for determining blockade of AMPA receptor activation-induced 45Ca2+ uptake is described below.
Primary cultures of rat cerebellar granule neurons are prepared as described by Parks, T. N., Artman, L. D., Alasti, N., and Nemeth, E. F., Modulation Of N-Methyl-D-Aspartate Receptor-Mediated Increases In Cytosolic Calcium In Cultured Rat Cerebellar Granule Cells, Brain Res. 652, 13-22 (1991). According to this method, cerebella are removed from 8 day old CD rats, minced into 1 mm pieces and incubated for 15 minutes at 37xc2x0 C. in calcium-magnesium free Tyrode""s solution containing 0.1% trypsin. The tissue is then triturated using a fine bore Pasteur pipette. The cell suspension is plated onto poly-D-lysine coated 96-well tissue culture plates at 105 cells per well. Medium consists of Minimal Essential Medium (MEM), with Earle""s salts, 10% heat inactivated Fetal Bovine Serum, 2 mM L-glutamine, 21 mM glucose, Penicillin-Streptomycin (100 units per ml) and 25 mM KCl. After 24 hours, the medium is replaced with fresh medium containing 10 xcexcM cytosine arabinoside to inhibit cell division. Cultures should be used at 6-8 DIV.
The effects of drugs on AMPA receptor activation-induced 45Ca2+ uptake can be examined in rat cerebellar granule cell cultures. Cultures in 96 well plates are preincubated for approximately 3 hours in serum free medium and then for 10 minutes in a Mg2+-free balanced salt solution (in mM: 120 NaCl, 5 KCl, 0.33 NaH2PO4 1.8 CaCl2, 22.0 glucose and 10.0 HEPES at pH 7.4) containing 0.5 mM DTT, 10 xcexcM glycine and drugs at 2xc3x97final concentration. The reaction is started by rapid addition of an equal volume of the balanced salt solution containing 100 xcexcM of the AMPA receptor agonist kainic acid and 45Ca2+ (final specific activity 250 Ci/mmol). After 10 minutes at 25xc2x0 C., the reaction is stopped by aspirating the 45Ca2+-containing solution and washing the cells 5xc3x97in an ice cold balanced salt solution containing no added calcium and 0.5 mM EDTA. Cells are then lysed by overnight incubation in 0.1% Triton-X100 and radioactivity in the lysate is then determined. All of the compounds of the invention, that were tested, had IC50s of less than 5 xcexcM.
The compositions of the present invention may be formulated in a conventional manner using one or more pharmaceutically acceptable carriers. Thus, the active compounds of the invention may be formulated for oral, buccal, transdermal (e.g., patch), intranasal, parenteral (intravenous, intramuscular or subcutaneous) or rectal administration or in a form suitable for administration by inhalation or insufflation.
For oral administration, the pharmaceutical compositions may take the form of, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g., lactose, microcrystalline cellulose or calcium phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycollate); or wetting agents (e.g., sodium lauryl sulphate). The tablets may be coated by methods well known in the art. Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, methyl cellulose or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters or ethyl alcohol); and preservatives (e.g., methyl or propyl p-hydroxybenzoates or sorbic acid).
For buccal administration the composition may take the form of tablets or lozenges formulated in conventional manner.
The active compounds of the invention may be formulated for parenteral administration by injection, including using conventional catheterization techniques or infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulating agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form for reconstitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.
The active compounds of the invention may also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.
For intranasal administration or administration by inhalation, the active compounds of the invention are conveniently delivered in the form of a solution or suspension from a pump spray container that is squeezed or pumped by the patient or as an aerosol spray presentation from a pressurized container or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount. The pressurized container or nebulizer may contain a solution or suspension of the active compound. Capsules and cartridges (made, for example, from gelatin) for use in an inhaler or insufflator may be formulated containing a powder mix of a compound of the invention and a suitable powder base such as lactose or starch.
A proposed dose of the active compounds of the invention for oral, parenteral or buccal administration to the average adult human for the treatment of the conditions referred to above (e.g., stroke) is 0.01 to 50 mg/kg of the active ingredient per unit dose which could be administered, for example, 1 to 4 times per day.
Aerosol formulations for treatment of the conditions referred to above (e.g., stroke) in the average adult human are preferably arranged so that each metered dose or xe2x80x9cpuffxe2x80x9d of aerosol contains 20 xcexcg to 1000 xcexcg of the compound of the invention. The overall daily dose with an aerosol will be within the range 100 xcexcg to 10 mg. Administration may be several times daily, for example 2, 3, 4 or 8 times, giving for example, 1, 2 or 3 doses each time.